Textile machines with uniform deceleration of its drive motors

ABSTRACT

Textile machines, particularly stretch-twist machines, with several electric drive motors arranged in succession in thread running direction, each motor driving one or more thread treatment or handling devices, e.g., thread-feed heating or stretching godets, winding devices or the like, said devices running at predetermined, adjustable speeds, for example, in a predetermined rpm ratio, or also at a constant thread speed and a predetermined, variable rpm pattern.

Lohest [4 June 12, 1973 TEXTILE MACHINES WITH UNIFORM 2,349,882 5 1944 Reichelt 57 93 x DECELERATION OF ITS DRIVE MOTORS 3,316,699 5/1967 Mattingly 57/93 lnventor: Hans Lohest, Remscheid, Germany Assignee: Barmag Barmer Mashinenfabrik Aktiengesellschaft, Wuppertal, Germany Filed: Nov. 23, 1970 Appl. No.: 91,945

US. Cl 57/100, 57/93 Int. Cl D011! l/20, DOlh l/22, DOlh 1/24 Field of Search 57/93, 94, 92, 100

References Cited UNITED STATES PATENTS 7/1970 Lamporter 57/93 X Loweller et al 57/94 X Primary Examiner-Donald E. Watkins Attorney-Johnston, Root, OKeeffe, Keil, Thompson & Shurtleff [57] ABSTRACT Textile machines, particularly stretch-twist machines, with several electric drive motors arranged in succession in thread running direction, each motor driving one or more thread treatment or handlingdevices, e.g., thread-feed heating or stretching godets, winding devices or the like, said devices running at predetermined, adjustable speeds, for example, in a predetermined rpm ratio, or also at a constant thread speed and a predetermined, variable rpm pattern.

6 Claims, 4 Drawing Figures TEXTILE MACHINES WITH UNIFORM DECELERATION OF ITS DRIVE MOTORS INTRODUCTION Machines of this type serve especially for the stretching, texturizing, twisting, rewinding or the like of synthetic threads. These machines are constructed in such a way that numerous thread treatment devices are located next to one another in a machine frame. Each individual thread treatment interval has several, generally three or four, devices rotating at differing rpms and arranged in succession in thread running direction. The drive of the thread treatment devices takes place either individually or more generally from a common motor for a parallel series of groups of identical devices. These groups, depending on the machine size, may extend along a complete machine side. The rpm ratio between the thread treatment devices is achieved by gear drives off one ormore gear shafts and/or belt drives or through electrical or electronic controlling and regulating devices.

Special devices are used for the accelerating of the textile machines to the operating speed, as well as for the switching off of the machines. It is essential that the thread quality is not diminished in the starting or stopping of the machine.

Devices of this general type are known. According to British Pat. No. 1,113,378, for example, all the drive motors are constructed as synchronous motors. They are fed, in correspondence to their speed of rotation, via frequency transformers and amplifiers from various alternating current sources with differing frequency. The frequencies of the alternating current sources and the frequency ratio necessary for the speed of rotation ratio are established by pulse sequences which are stored in a multitrack magnetic tape. This assures an absolute synchronization of all the motors. The drive motors of the textile machine are started by slow acceleration of the magnetic tape and in the switching off are stopped synchronously by braking of the magnetic tape.

Devices of this type, however, because of the differing frequencies required, demand a considerable expenditure in electronic devices, which is not economically justified in every case. Furthermore, frequently for a part of the thread treatment devices, e.g., the winding devices or twist spindles, direct current motors are used, since the turning speed of these devices has to be continuously regulated over a wide range. For example, in the case of twist spindles, such regulation is necessary in order to make it possible to maintain constant the winding speed of the thread and the thread tension during the winding process as the spool diameter increases. ln the case of miscellaneously equipped textile machines which have both synchronous motors and also direct current motors or also three-phase motors, the type of synchronization described in British Pat. No. 1,113,378 cannot be used, whereby considerable difficulties are still presented especially in connection with the uniform deceleration of all of the drive motors.

This is due to the fact that the shafts of the motors, because of the mechanical structure of the individual thread treatment devices, are loaded with differing moments of inertia. Furthermore, for the spindle drives, depending on the switch-off time point, it is necessary to reckon with different thread masses of the respective windings. Without influencing of the drive motors in a stretch twist machine, for example, the drive motor for the twist spindles will decelerate less rapidly than the drive for the heating godets and delivery mechanisms. The thread tensioned in the machine would be overstretched and would finally break. This situation must absolutely be avoided in practice, since otherwise the machines can no longer be started without spool change.

With this state of technology there exists the problem of providing means for the uniform deceleration of textile machines of the type mentioned, in which additional electrical or electronic controlling and regulating devices or the like are, insofar as possible, completely eliminated. Such means nevertheless influence the various drives of a textile machine in such a way, particularly in switching off of the machine, that even independently of the thread masses of the respective windings, there is assured a uniform deceleration of the drives.

THE INVENTION This problem is solved according to the invention by the means that all the drive electric motors are direct current motors, whose armature windings, for example by means of a switch, are connected either for the drive with one or more direct current sources or for the deceleration of the machine, directly or indirectly with one another. In the switching off and stopping of a machine thus equipped, it suffices to release the drive motors with the aid of the switch mentioned from the feed main and to switch the armature windings of the motors parallel to one another. Through this switching arrangement, the circuit for the motor acts as generator (in the manner of the Leonard principle) on whose terminals the greatest electromotive forces is generated by the moment of inertia acting on the shaft.

In stretch twist machines it has proved especially advantageous if the circuit is laid out in such a way that the electric motor which serves for the drive of the winding device operates as a generator, in this case for the drive of the spindles of the stretch-twisting ma chine. This can be realized by using in the connecting line of the armature winding of the spindle drive motor and of the other motors a diode in such a way that its cathode is connected with the pole of the armature winding which is the minus pole in generator drive of the spindle drive motor. The diode prevents any current flow in reverse direction. A synchronization occurs, therefore, only if which is always the case in practice the drive motor of the spindle is the motor with the longer deceleration rate or time.

Especially in the case of relatively large machines it may be desirable to limit the deceleration time of the drives. This can be achieved by engaging in series in the same direction several diodes or by interposing between the armature windings, in addition to the diode or diodes, current limiting resistors, for example ohmic resistors.

Through the dimensioning of the resistors in the deceleration circuit, also the thread tension on the spools after the switching off of the drives of the stretch-twist machine is established. If the electromotive force induced by the spindle drive becomes too low to overcome the resistances in the deceleration circuit, the other drive motors engaged parallel to the spindle drive motor remain at or come to a standstill. The spindle drive runs along briefly and thereby tensions the thread between the spool and the other thread treatment devices.

In order to separate the armature windings from the feed main or mains and to connect them virtually immediately thereafter, as a rule there will be provided a simple mechanical switch for the switching off of the textile machine. Depending on the construction and power of the machine, the switch, however, can be replaced also by a magnetic relay or by electronic devices, for example transductors, thryistors or the like.

THE DRAWINGS The invention is explained in detail in the following with the aid of the drawings wherein:

FIG. 1 is a side elevation of an embodiment of a stretch twist machine;

FIG. 2 is a circuit diagram for the drive motors of the stretch twist machine of FIG. 1;

FIG. 3 is a graph of the course of the terminal voltages of the drive motors in the circuitry of FIG. 2 after the moment of switch-off; and

FIG. 4 illustrates a portion of the circuit diagram of FIG. 2 with more than one diode in series.

THE ILLUSTRATED EMBODIMENT In the stretch twist machine represented in FIG. 1 on both sides of the machine frame 1, in running direction of the thread 2 (from the top downward) there are arranged the following devices: the delivery mechanisms 3, the heating godets 4 and the winding devices 5, e.g., ring-twist spindles. The direct current motor 6 which is mounted in the drive casing 7 at the level of the heating godets 4, drives the delivery mechanisms 3 and the heating godets 4 simultaneously. Between the motor 6, the delivery mechanisms 3 and the heating godets 4 is a transmission 8, e.g., a reduction gear box and/or drive belt couplings. The delivery mechanisms 3 can also be driven separately by the direct current motor 6a and the transmission 8a drawn in broken lines. For the spindles there is likewise provided a direct current motor 9 accommodated on the drive casing 7, which sets the spindles 5 in rotation by the drive belts 10.

The threads 2 run from the delivery mechanisms 3 over the heating godets 4 onto the spools 5. Delivery mechanisms 3, heating godets 4 and spools of the winding device 5 rotate at different circumferential velocities. For the generation of the desired thread quality there is maintained a fixed circumferential velocity ratio, or rotation speed ratio, between the respective thread treatment devices 3 to 5.

In the circuit of FIG. 2, a simple, mechanical, multipole switch 11 is shown in closed position. The direct current motors 6 and 9 represented in FIG. 2 are outside-excited direct current motors. The drive motor 61, which can be provided in the case of a separate drive of the delivery mechanisms 3, is shown in broken lines in parallel circuit to the direct current motor 6. Each motor has an independent outside excitation circuit 6b, 6b and 9b with respective rotor windings 6c, 60 and 9c. In the working position of the switch 11, the armature windings 6 and 9 of the direct current motors 6 and 9 are connected over the switch contacts 12/13 and I7/l 8 and, respectively, switch contacts 15/16 and 19/2011, with the direct current sources 21 and 22.

In the shifting of the switch 11 into the position for the deceleration of the motors 6 and 9, the contacts l2/l4 and 17/20b are connected. The contacts 13,16

and 18 and 20a are open. In the connecting conductor 23, now energized between the direct current motors 6 and 9, there is a diode 2 4 and an ohmic resistor 25. The diode 24 is installed in such a way that its cathode 26 is connected with the minus pole 27 of the terminals of the direct current motor acting as a generator over the switching contact 12/14. The circuit of the motors may have several diodes in series as illustrated in FIG. 4.

FIG. 3 shows in a schematic diagram the dependence of the terminal voltage U of the direct current motors 6 and 9 on the deceleration time t after throwing of switch 11 into the deceleration position according to FIG. 2. The terminal voltage U is in proportional relationship with the turning speed n of the motors because of the constant magnetic flux in outside excitation.

The terminal voltage U is plotted in the diagram of FIG. 3 in vertical direction, the deceleration time t in horizontal direction. Without influencing of the decelerating drive motors per the invention herein, the terminal voltage U (6) for the drive motor 6 of the delivery mechanisms 3 and godets 4 falls according to the straight line 28 from the point t to the standstill of the drive at time point 2 The course of the terminal voltage U (9) on the terminals of the drive motor 9 for the spindles takes place, because of the greater moment of inertia coming into play, according to the less steep straight line 29. The spindle drive stops at the time point t.,.

Through the connection according to the invention of the armature windings of the direct current motors 6 and 9 and through the use of a diode 24 in the connecting line 23 according to FIG. 2, from the time point t onward the terminal voltage U (6) on the drive motor 6 through the induced electromotive force on the spindle drive motor 9 follows along the straight line 30 parallel to the straight line 29. The amount of the terminal voltage U (6) is smaller than the terminal voltage U (9) by the threshold value voltage loss of the diode 24 and by the voltage loss which arises through the resistor 25 in the connecting line 23. By threshold value voltage loss of a diode there is meant the voltage which is necessary as minimum voltage to make the diode conducting in pass direction. Because of these losses the drive motor 6 stops at the time point 2 The spindle drive runs on until the time point z, and thereby keeps tension in the thread between the heating godets 4 and the spindles 5. The schematic diagram of FIG. 4 shows that the after-running of the spindle drive motor 9 and thereby the provided thread tension in the selected circuit for the uniform deceleration of textile machines depends on the difference between the electromotive force induced by the spindle drive motor 9 and the voltage loss in the deceleration circuit. The desired thread tension on the spools after the switching off of the direct current motors, therefore, is established, like the deceleration time 1 of the spindle drive 9, i.e., by dimensioning the threshold value voltage loss of the diodes 24 and by dimensioning the resistances 25 in the connecting line 23 between the armature windings of the drive motors 6 and 9.

It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, and form herein disclosed being a preferred embodiment for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

ll. A textile machine with several electric drive motors driving thread-handling components having different moments of inertia and arranged successively in thread running direction, characterized by all of the said electric drive motors being direct current motors and circuit means having armature windings connected with one or more direct current sources by switch means providing simultaneous excitation thereof and simultaneous disconnection from said direct current sources, said switch means thereby providing substantially simultaneous deenergization of said motors for deceleration of the machine.

2. A machine as claimed in claim 1, wherein said armature windings of respective motors are electrically coupled in parallel circuits.

3. A machine as claimed in claim 1, wherein one of said motors drives a thread-winding mechanism with large moment of inertia, the armature windings of said last-mentioned motor being connected with the armature windings of the other motor or motors by circuit means including a diode, in such a way that the cathode of which is connected with that pole of the armature winding of said thread-winding drive motor which is the minus pole in generator operation of the threadwinding drive motor.

4. A machine as claimed in claim 2, wherein one of said motors drives a thread-winding mechanism with large moment of inertia, the armature windings of said last-mentioned motor being connected with the armature windings of the other motor or motors by circuit means including a diode, in such a way that the cathode of which is connected with that pole of the armature winding of said thread-winding drive motor which is the minus pole in generator operation of the threadwinding drive motor.

5. A machine as claimed in claim 3, wherein said circuit means has several of said diodes in series.

6. A machine as claimed in claim 3, wherein said circuit means includes at least one resistor in series with said diode. 

1. A textile machine with several electric drive motors driving thread-handling components having different moments of inertia and arranged successively in thread running direction, characterized by all of the said electric drive motors being direct current motors and circuit means having armature windings connected with one or more direct current sources by switch means providing simultaneous excitation thereof and simultaneous disconnection from said direct current sources, said switch means thereby providing substantially simultaneous deenergization of said motors for deceleration of the machine.
 2. A machine as claimed in claim 1, wherein said armature windings of respective motors are electrically coupled in parallel circuits.
 3. A machine as claimed in claim 1, wherein one of said motors drives a thread-winding mechanism wIth large moment of inertia, the armature windings of said last-mentioned motor being connected with the armature windings of the other motor or motors by circuit means including a diode, in such a way that the cathode of which is connected with that pole of the armature winding of said thread-winding drive motor which is the minus pole in generator operation of the thread-winding drive motor.
 4. A machine as claimed in claim 2, wherein one of said motors drives a thread-winding mechanism with large moment of inertia, the armature windings of said last-mentioned motor being connected with the armature windings of the other motor or motors by circuit means including a diode, in such a way that the cathode of which is connected with that pole of the armature winding of said thread-winding drive motor which is the minus pole in generator operation of the thread-winding drive motor.
 5. A machine as claimed in claim 3, wherein said circuit means has several of said diodes in series.
 6. A machine as claimed in claim 3, wherein said circuit means includes at least one resistor in series with said diode. 